Thin, self-supporting, ductile, plastic target sheet

ABSTRACT

A one-piece, self-supporting target made of relatively rigid, ductile synthetic plastic material having low shock transference characteristics. The target is formed with longitudinal and transverse strengthening formations, and, due to its thickness and ductility, a projectile passing through the target forms a flanged hole having dimensions less than the corresponding dimensions of the projectile.

United States Patent [15] 3,682,478 Knight Aug. 8, 1972 [54] THIN,SELF-SUPPORTING, DUCTILE, 3,088,738 5/1963 Meyer ..273/102 B PLASTICTARGET SHEET 3,353,827 11/1967 Dun ..273/D1G. 4 72 Inventor: LindsaCharles Kni 42 2,560,742 7/1951 Reder ..46/76R 1 f, Ave Album South2,896,370 7/1959 De Wm ..46/79 wales, Australia 3,409,301 11/1968 Studen..273/102 B 3,516,670 6 1970 D t' ..27 22 Filed: Jan. 31, 1969 I Agos3/102 2 R [21] Appl. No.2 795,639 Primary Examiner-Richard C. PinkhamAssistant Examiner-Marvin Siskind [30] Foreign Application Priority DataAttorney-Oberlin, Maky, Donnelly & Renner Feb. 8, 1968 Great Britain..6,297/68 [57] ABSTRACT 52 US. (:1 ..273/102.2 s, 273/010. 4, 248/453,4 P -P self-supwning mafia @Iatively 200/6145, 273/1023 llgld, ductilesynthetic plastic material havmg low 51 Int Cl. ..F4lj 3/00 Shocktransference characteristics- The target is 58 Field of Search..273/102, 102 B, formed with n i d n andlransverse Strengthening 46/76,79 formations, and, due to its thickness and ductility, a projectilepassing through the target forms a flanged hole having dimensions lessthan the corresponding [56] References Cited dimensions of theprojectile.

UNITED STATES PATENTS 5 Claims, 7 Drawing Figures PATENFED 8|9723,682,478

sum 1 OF 2 3,682,478 1 2 THIN, SELF-SUPPORTING, DUCTILE, PLASTIC memberwhich extends in a plane adjacent to and TARGET SHEET This inventionrelates to improvements in target apparatus and relates particularly toimprovements in apparatus for use with target mechanisms of the typewhich include automatic hit detecting and hit counting apparatus.

Target mechanisms of this type employ means for detecting and countingthe number of hits on a target, usually of ply-wood construction, andhave other means for transmitting this information to a controlposition.

It has been found with target mechanisms presently used that the hitdetecting and counting means are erratic and therefore inaccurate. Thusthe apparatus either does not count all the hits on the targets orcounts as hits, stone showers, muzzle blasts and near misses.

This erratic operation becomes more apparentwith changes in climaticconditions, and causes the" apparatus to be unsatisfactory in extremeclimatic conditions.

It is believed that a factor which contributes to the erratic operationof the apparatus is the mounting used to mount the target on the targetapparatus. Normally this mounting consists of a clamp which is fixed tothe apparatus and clamps about the base of the target.

Another factor which, it is believed, contributes to the inaccuratecounting of hits on a target, is the properties of the material fromwhich the target is made. Requirements of target apparatus of this typeis that the target has a relatively long life e.g. that it can take alarge number of hits without disintegrating, remains effective incounting while in use and is relatively cheap. Targets at presentlyused, however, do not meet all these requirements.

Additionally, targets generally used on target apparatus havingautomatic hit detecting, hit counting, and target fall facilities havebeen made of materials having relatively high shock transferencecharacteristics so that relatively simple types of hit detectingtransducers, such as microphones, micro-switches and the like can beemployed to detect the shock waves set up in the target by the impact ofa bullet therewith. The use of a target material which does not havethis property of high shock transference has previously created problemsof reliable and satisfactory hit detection.

A further factor which it is believed also contributes to the inaccurateoperation of the target apparatus is the relatively crude transducerdevices and associated circuitry as presently used to detect a hit onthe target. Devices now used include inertia and micro switches andmicrophones.

It is an object of the present invention to provide an improvedconstruction of target apparatus which alleviates the aforementioneddisadvantages and overcomes the factors which contribute to the erraticoperation of the apparatus.

A still further object of the invention is to provide an improved targetfor use with the target apparatus.

According to one aspect of the invention there is provided a targetholder for mounting a target on a base, said holder comprising anelongated front portion having target engaging member which is formedwith at least one rearwardly extending projection, an elongated rearportion having a second target engaging parallel, or nearly parallel, tosaid first target engaging member, the upper edge portion of said secondtarget engaging member having at least one slot therein which dividesthe edge portion into at least two parts, each part being deformed outof the plane of the member to form further projections and adjustablemeans coacting with both said front and rear portions to enable a targetto be securely clamped between said portions so that said projectionsengage with and deform the target.

Preferably, the target holder is used with a target comprising a sheetof relatively rigid, ductile synthetic plastic material having low shocktransference qualities and being formed with strengthening ribs, flangesor formations to provide a rigid body. The target is also provided onits lower edge portion with means to enable the target to be supportedand moved thereby.

It is preferred that the target be moulded of polyethylene sheet ofbetween to 200 thousandths of an inch thickness having longitudinallyextending strengthening ribs and a part peripheral flange about the sideand upper edge portions.

The invention further provides an improved inertia switch typetransducer comprising an elongated base of electrically insulatingmaterial having an electrical contact point fixed thereto at one endthereof, a leaf spring having a second electrical contact point attachedto one end thereof said spring being mounted by its other end to thebase so that said contact points are engaged and adjusting means engagedwith said leaf spring part way along its length to vary the tension onthe spring and the force holding said contact points in engagement. Theadjusting means may comprise a bracket extending portion of the lengthof the spring and a screw threaded through the bracket and arranged tobear on the spring.

Alternatively, the adjusting means may be incorporated in a casing inwhich the transducer is mounted. The casing, comprising a metallic boxhaving a removable lid, has an elongated bracket fastened by one end ofthe lid and extends over the spring in the same direction thereof. Meansare provided for moving the free end of the bracket towards or away fromthe lid and further means are provided to transmit this motion to saidspring to decrease or increase the tension in the spring.

In order that the invention may be more readily understood and put intopractical form, embodiments thereof will now be described with referenceto the drawings wherein:

FIG. 1 is a plan view of a target holder made according to theinvention;

FIG. 2 is an end elevation of the target holder of FIG.

FIG. 3 is a rear elevation of the target holder of FIG. 1 and having atarget mounted therein;

FIG. 4 is a sectional plan view of a target made in accordance with thepresent invention;

FIG. 5 is a side view of an inertia switch type transducer madeaccording to this invention;

FIG. 6 is a plan view of the transducer of FIG. 5; and

FIG. 7 is a sectional side view of a modified construction oftransducer.

Referring to FIGS. 1 to 3 of the drawings, the target holder comprisestwo elongated members 11 and 12 angles to the base portion 13, and isprovided with four studs 18 which are fixed to and extend rearwardlyfrom the part 17.

A rearwardly extending deformation 19 is formed in the upper edgeportion of the part 17 approximately mid-way between the side edgesthereof. The deformation 19 is of semi-circular shape and projects fromthe plane of the part 17 at the upper edge thereof a distance equal toapproximately half of the thickness of the part 17.

The rear portion of the holder has a second target engaging part 21extending upwardly from the base portion 14 and makes an angle with thebase portion 14 which is less than a right angle. Four holes 22 areformed in the part 21 through which the studs 18 pass.

Two slots 23 are formed in the upper edge portion of the part 21 and thesections 24 and 25 between the slots 23 and the ends of the part 21 arebent forwardly so that the upper edge 26 and 27, in plan view, form an 4are of a circle. The center part 28, between the slots 23 is also bentforwardly at a small angle so that the upper edge thereof projects fromthe plane of the part 21 a distance approximately equal to half thethickness of the part 21.

The two members are arranged to be mounted backto-back on a targetmounting base and spaced apart at their-base portions a distanceapproximately equal to the thickness of a target to be mountedtherebetween. A target 32 is inserted in the wedge shaped space 31between the two upwardly extending parts 17 and 21, the target havingslots 33 formed or cut in the base portion 34 thereof cooperating withthe studs 18. Wing nuts 36 are screwed onto the studs 18 and aretightened to clamp the target 32 between the parts 17 and 21. Theprojection or deformation 19 is impressed into the front face 37 of thetarget 32 and the edges of the sections 24 and 25, and the center part28 of the rear part 21 are firmly impressed into the rear surface of thetarget 32. The outer comers 38 of the sections 24 and 25 may be relievedto prevent stress points being set up in the side portions of the target32.

The target 32, as shown in FIGS. 3 and 4, comprises a sheet ofrelatively ductile polyethylene which has a low shock transferencequality moulded to form a rigid self-supporting body.

The target 32 is moulded from sheet polyethylene of between about 0.050to 0.150 inches thick. The side or peripheral edges 41 of the target 32,except at the base thereof, are formed at right angles to the plane ofthe target 32 to provide strengthening flanges. Further stiffness orrigidity is provided by four longitudinally extending ribs 42, the outerpair of which angle outwardly at the bottom thereof, as shown at 43.These ribs may vary in shape and position from those shown to increasethe longitudinal and/or lateral bending strength of the target as, forexample, a relatively tall target know as standing-man targets, so thatthe target may be quickly moved from an upright, operative position to ahorizontal, inoperative position by suitable known target movingmechanisms.

The polyethylene target material is formed to provide a double targetover a temperature range of between about F and 130 F and which resistscracking and breaking when a bullet, or other projectile, passestherethrough. The target has a memory" so as to tend to restore itselfto its original condition after the passage of a bullet through thetarget. Thus, when a bullet passes through the target the bulletinitially deforms the target material and fomis a flanged opening. Whenthe bullet has passed through the flanged hole the flanges tend to closearound the hole to restore the target to its initial condition. Anybullet passing through or adjacent that hole will then be registered byhit detecting means associated with the target apparatus. The memoryeffect of the target material also increases the life of the target asthe target material is not removed by the passage of a bullettherethrough.

In use, the target'is suitable for use at low and high temperatureswithout splintering or cracking when struck by bullets of size rangingfrom 0.223 to 9mm and 0.38 military type ammunition, and impacttransference is satisfactory to permit use of the target on known targetapparatus. In particular, the use of the target in conjunction with theimproved hit detecting transducer of the present invention producesexcellent results of hit counting.

The transducer, as shown in FIGS. 5 and 6, comprises an elongated base51 of rigid electrically insulating material having a transverselyextending electrically conducting strip 52 mounted in a groove fonnedadjacent one end thereof. The conducting strip 52 carries a firstelectrical contact point 53 in the middle thereof. A second contactpoint 54 is mounted on one end of an elongated electrically conductingleaf spring 56 which is clamped by its other end between a bracket 57and the base 51 by screws 58. The leaf spring 56 is formed with anoffset 59 in approximately the middle thereof which raises the plane ofthe first end portion away from the plane of the base 51.

At one end of the bracket 57, adjacent the offset 59 in the leaf spring56, there is formed a threaded hole, and a spring tensioning screw 61having a locknut 62 is threaded therein. The end of the screw 61 engageswith the leaf spring 56 and applies pressure thereto to cause the secondcontact point 54 to engage with the first contact point 53. Furtherpressure applied by the screw 63 by the adjusting screw 61 to increasethe pressure in the contact points 53 and 54.

In use, the transducer is mounted in a casing which is attached to thefront of a target holder so that the base 51 is adjacent the targetholder and the leaf spring 56 is forwardly thereof. When the targetmounted in the target holder is struck by a bullet, the impact istransferred to the transducer which moves with the target holder. Theinertia of the impact determines the rate of movement of the transducer.As the base 51 begins to move at the rate determined by the impact thecontact points tend to open due to the inertia of the leaf spring 56.

Thus the resistance across the points increases. By adjustment of thetension in the leaf spring the amount of resistance increase for a givenimpact can be controlled so that an electrical circuit connected withthe contact points may be activated when the resistance rises to apredetermined level. The impact of a bullet on the target may then bearranged to activate the electrical circuit whereas the impact of anear-miss (the shock-wave produced in the air by the bullet) or of astone shower produced when the bullet falls short of the target do notactivate the electrical circuit.

In the embodiment shown in FIG. 7 the transducer switch is of the sameconstruction as that described above except that the leaf springtensioning screw 61 and locknut 62 are omitted. The switch is mounted ina cast metal casing 66 and is held in place by screws 67. A lid 68 isprovided for the casing 66 with an elongated bracket 69 mounted by oneend to the inside surface of the lid 68. The bracket 69 is provided withan offset 71 so that the other end of the bracket extends in a planesubstantially parallel to but spaced from the lid inner surface.

A pin 72 is positioned in a hole formed in the end of the leaf springclamping bracket 57 and engages with the leaf spring 56 and anindentation 73 formed in the bracket 69.

An adjusting screw 74 threaded through a hole 76 in the lid 68 engageswith the free end of the bracket 69 in a manner such that the bracket ismoved with movement of the screw 74. A locknut 77 is provided for thescrew 74. Also, an indicator dial 78 may be provided on the adjustingscrew 74.

It will be seen that the transducer switch of this embodiment may beadjusted externally of the casing 66 thus permitting adjustment to bemade during use of the target apparatus on which the switch is mountedwithout disassembling any of the apparatus.

What I claim is:

1. A one-piece, self-supporting target comprising a generally elongatedsheet of relatively rigid, ductile synthetic plastic material of athickness between 0.100 and 0.150 inches, said plastic material havinglow shock transference characteristics and being formed withlongitudinal strengthening formations, the thickness and ductility ofsaid plastic material being such that a projectile passing therethroughforms a flanged hole having dimensions less than the correspondingdimensions of the projectile.

2. The target of claim 1 wherein said synthetic plastic material ispolyethylene.

3. The target of claim 1 further including transverse strengtheningformations, and wherein said longitudinal and transverse strengtheningformations comprise ribs moulded into the material.

4. The target of claim 1 further including a peripheral flange formedabout the side and upper edges of the target to provide peripheralrigidity to the structure.

5. The target of claim 1 wherein said synthetic plastic material ispolyethylene and said longitudinal strengthening formations compriseribs moulded into the material, and further including a peripheralflange formed about the side and upper edges of the target to provideperipheral rigidity to the structure.

1. A one-piece, self-supporting target comprising a generally elongatedsheet of relatively rigid, ductile synthetic plastic material of athickness between 0.100 and 0.150 inches, said plastic material havinglow shock transference characteristics and being formed withlongitudinal strengthening formations, the thickness and ductility ofsaid plastic material being such that a projectile passing therethroughforms a flanged hole having dimensions less than the correspondingdimensions of the projectile.
 2. The target of claim 1 wherein saidsynthetic plastic material is polyethylene.
 3. The target of claim 1further including transverse strengthening formations, and wherein saidlongitudinal and transverse strengthening formations comprise ribsmoulded into the material.
 4. The target of claim 1 further including aperipheral flange formed about the side and upper edges of the target toprovide peripheral rigidity to the structure.
 5. The target of claim 1wherein said synthetic plastic material is polyethylene and saidlongitudinal strengthening formations comprise ribs moulded into thematerial, and further including a peripheral flange formed about theside and upper edges of the target to provide peripheral rigidity to thestructure.